Spotting fluid and method of treating a stuck pipe

ABSTRACT

The method for releasing the stuck pipe of the present invention uses a combination of components which oxidize the mud cake and generated gas bubbles to create an upward buoyancy for the oxidized mud cake. The spotting method of the present invention comprises adding to the borehole in the region of the stuck pipe: 1) an oxidizer which oxidizes the mud cake; and 2) at least one component which reacts in the borehole to generate a gas. Optionally, but preferably, the spotting method further uses a lubricant which is added to the borehole in the region of the stuck pipe. The lubricant acts to lubricate the oxidized parts of the mud cake. Also disclosed is a spotting fluid system comprising 1) an oxidizer which oxidizes the mud cake, 2) at least one component which reacts in the borehole to generate a gas, and, optionally a lubricant which acts to lubricate the oxidized parts of the mud cake.

TECHNICAL FIELD

[0001] The present invention relates to a spotting fluid system used todislodge a stuck drill pipe in subterranean drilling operations. Inaddition, this invention relates to a method of dislodging a stuck drillpipe which is lodged in subterranean formations.

BACKGROUND OF THE INVENTION

[0002] The drilling of oil and gas wells is accomplished by using rotarydrilling techniques. In these rotary drilling techniques, a drilling mudis circulated through the drill pipe, out the bit nozzles and it isreturned to the surface via an annulus. The drilling mud serves to cooland lubricate the drill bit and drill pipe. In addition, the drillingmud develops a hydrostatic head to counterbalance formation pressuresand removes cuttings from the borehole. Further, the drilling mud helpsreduce the friction forces between the drill pipe and the borehole.

[0003] Even though a drilling mud is used during the subterraneandrilling operations, drill bits and drill pipes still become lodged insubterranean formations from time to time. The term “stuck pipe” isconventionally used in the drilling industry to describe this problem.“Stuck pipe” is not limited to drill pipes, but includes drill pipes,drill collars, drill bits, stabilizers, reamers, casings, tubing andother items or tools which may become lodged in drilling operations.When a stuck pipe becomes lodged, it can not be raised, lowered orrotated. A stuck pipe increases the cost of drilling a well due todowntime of the drilling operation. In extreme cases, a stuck pipe maycause the abandonment of the drilling operation at a particular site, ifthe stuck pipe can not be economically released.

[0004] There are many causes of stuck pipe. The industry categorizes thecauses as either differential or mechanical sticking.

[0005] Differential sticking occurs during most drilling operations. Thehydrostatic pressure exerted by the drilling mud column is greater thanthe formation fluid pressure. In permeable formations, the mud filtrateflows from the borehole into the rock pores and builds up a filter cake.A pressure differential exists across the filter cake which is equal tothe difference between the pressure of the mud column and the pressureof the formation.

[0006] When a pipe is central in the borehole, the hydrostatic pressure,due to the mud overbalance, acts in all directions around the pipe. If,however, the pipe touches the filter cake, the mud overbalance acts topush the pipe further into the filter cake, thus increasing the contactarea between the pipe and the filter cake. Filtrate is still expelledand squeezed from the filter cake between the pipe and the formationthus shrinking the cake and allowing the pipe to penetrate further intothe filter cake, thereby further increasing the contact area. If thepressure difference is high enough and acts over a sufficiently largearea, the pipe may become stuck. Differential sticking usually occurswhen the pipe has been motionless for a period of time, e.g., whenmaking a pipe connection or during surveying.

[0007] The force required to pull differentially stuck pipe free dependson many factors including:

[0008] (1) The difference in the pressure between the borehole and theformation. Any overbalance adds to side forces which may exist due tothe deviation of the hole.

[0009] (2) The surface area of the pipe embedded in the wall cake. Thethicker the cake or the larger the pipe diameter, the greater this areagenerally is.

[0010] (3) The bond developed between the pipe and the wall cake is avery significant factor, being directly proportional to the stickingforce. This can include frictional, cohesive and adhesive forces. Itgenerally tends to increase with time, making it harder to pull the pipefree.

[0011] Differential sticking may be distinguished from other forms ofsticking, such as mechanical sticking. Mud circulation is notinterrupted as there is no obstruction in the borehole to stop the flow,as would be the case for pipe stuck due to hole bridging or caving. Itis not possible to move or rotate the pipe in any direction.

[0012] When a pipe sticks, the driller usually tries to free it bymechanical movement, e.g., by pulling, jarring or, if the pipe wasmoving immediately prior to sticking, trying to move the pipe in theopposite direction. Frequently this fails to release the pipe and thereis, of course, a limit to the force which can be applied, since too muchforce could pull the pipe apart and make the situation worse.

[0013] If the pipe remains stuck, it is then sometimes the practice toapply a pipe release agent, commonly called a “spotting fluid”. Thesespotting fluids are chemically active mixtures, which may be oil orwater based, which are placed over the stuck region in an attempt tofree the pipe, if mechanically working the pipe fails to release thepipe. These spotting fluids are believed to act by attacking the mudfilter cake. They are positioned in the borehole by pumping the spottingfluid down the hole to the stuck region in the form of a slug, alsoknown as a pill. The pill generally contains sufficient material tocover the stuck zone and extend slightly beyond the area of the stuckzone. Pills frequently are left to soak the cake until the pipe is freeor attempts to free the pipe are abandoned.

[0014] Over the years, many spotting fluids and spotting methods havebeen developed to lubricate the area of the stuck pipe which has becomelodged and to aid in the releasing of the drill bit from the formation,freeing a stuck drill pipe.

[0015] In one prior art stuck pipe treatment, hydrocarbon oils, such asdiesel oil, are injected into the borehole in the area of the stuckpipe. The mixture of the diesel oil and drilling mud provides a lowdensity, lubricating environment around the stuck point of the drill.Further, the hydrocarbon rises due to its buoyancy, which causes theremoval of the mud around the stuck point and makes well bore pressure(P_(w))≦the formation pressure (P_(f)) See, for example, U.S. Pat. No.3,217,802 to Reddie.

[0016] Attempts have been made to improve the effectiveness ofhydrocarbon based spotting fluids by adding additional components to thehydrocarbon based spotting fluids. For example, U.S. Pat. No. 5,671,810to Hodge et al. adds a carboxylic acid or a polycarboxylic acid and asurfactant to a hydrocarbon spotting fluid; U.S. Pat. No. 4,436,638 toWalker et al., adds a propoxylated C₁₈-C₃₂ alcohol and an oil solubleemulsifier to a hydrocarbon based spotting fluid; and U.S. Pat. No.4,427,564 to Brownawell et al. adds a propoxylated lactone acid and anoil soluble emulsifier to a hydrocarbon based spotting fluid.

[0017] In a different approach, U.S. Pat. No. 2,900,026 to Trusheimdiscloses the addition of at least a 10 percent solution of hydrogenperoxide to a borehole having a stuck drill pipe to disintegrate thewall cake which causes the lodging to the drill pipe. In addition, thispatent teaches that the addition of a small amount of caustic soda andsoda will aid the action of the hydrogen peroxide.

[0018] Aqueous spotting fluids have also been previously used in theart. U.S. Pat. No. 4,466,486 to Walker discloses a method for freeingstuck drill pipes by adding a mixture of water or brine with a cellulosepolymer or a polyether polymer as a spotting fluid. Further, othermethods for freeing stuck pipes include using water-based spottingfluids, such as U.S. Pat. No. 4,230,587 to Walker, which discloses amixture of water or brine with a mixture of polyethylene glycols as aspotting fluid; U.S. Pat. No. 4,494,610 to Walker, discloses a spottingfluid comprising a lower alcohol with another component, such as water,and optionally weighting agent; and U.S. Pat. No. 4,614,235 to Keener etal., discloses adding a mono or polyalkylene glycol ether to a waterbased spotting fluid.

[0019] Recently, acid and ester based spotting fluid have been preparedand used to release stuck pipes. In particular, a carboxylic acid, suchas acetic acid as is disclosed by U.S. Pat. No. 5,247,992 to Lockhart;fatty acid alkyl esters containing spotting fluids are disclosed by U.S.Pat. No. 4,964,615 to Mueller et al.; and a spotting fluid which isnon-toxic and comprises glycerol-phosphoric acid ester and a polyacyloxypolycarboxylic acid esters of mono and/or diglycerides is disclosed inU.S. Pat. Nos. 5,002,672 and 5,127,475 to Hayes et al.

[0020] Finally, a multi-step spotting method is disclosed by U.S. Pat.No. 5,415,230 to Fisk, Jr. et al. In the first step of this patent, aspotting pill containing brine is pumped into the region of the stuckpipe and allowed to soak. A second spotting pill is pumped into theregion of the stuck pipe and is also allowed to soak. The secondspotting fluid can be any spotting fluid known to those skilled in theart. The spotting fluid is allowed to soak in place for an extendedperiod or until the pipe becomes free.

SUMMARY OF THE INVENTION

[0021] The present invention employs a very different approach employinga multi-component addition to the borehole. The method for releasing thestuck pipe of the present invention uses a combination of componentswhich oxidize the mud cake, and generates gas bubbles through reactionwith the mud cake to create an upward buoyancy for the oxidized mudcake, as well as general lightening of the hydrostatic head column atthe same time. The spotting method of the present invention comprisesadding to the borehole in the region of the stuck pipe:

[0022] 1) an oxidizer which oxidizes the mud cake;

[0023] 2) at least one component which reacts in the borehole togenerate a gas; and

[0024] 3) optionally, at least one component which contains a reducer.

[0025] In a second aspect of the present invention the spotting methodfurther uses a lubricant which is added to the borehole in the region ofthe stuck pipe. The lubricant acts to lubricate the oxidized parts ofthe mud cake and the pipe.

[0026] In a third aspect of the present invention, a spotting fluidsystem is disclosed. The spotting fluid system comprises at least twoseparate components, a) an oxidizer which oxidizes the mud cake; and b)at least one component which reacts in the borehole with the oxidizer togenerate a gas. The spotting fluid system can optionally contain alubricant which acts to lubricate the oxidized parts of the mud cake andthe pipe. In addition, an article of manufacture comprising at least twoor three separate containers, depending whether or not the lubricant ispresent. A first container or containers comprise the oxidizer, a secondcontainer or containers comprise a component, which will react in theborehole to generate gas bubbles and a third container or containers,which are optional, comprise the lubricant. Additionally, a reducer canbe added to one of the containers, provided it will not react with theother components in the container. As an alternative, the reducer can bepresent in a separate container.

[0027] Another aspect of this invention is a method for dislodging astuck pipe in a borehole of a downhole well drilling operation whichcomprises adding to the borehole a solution comprising (i) an hydrogenperoxide and (ii) water or brine. It has been discovered that ofsolution of hydrogen peroxide, at a relatively low concentration, can beused to dislodge a stuck pipe, if the a drilling mud comprises, as adrilling fluid, at least one of the following modules (A)-(E)

[0028] (A) an alkaline first module that contains (a) a source ofcaustic, (b) a natural wax, (c) a natural thinner, (d) glycerol, and (e)phosphoric acid and/or boric acid,

[0029] (B) a second module prepared by reacting (f) aluminum metal withthe components of said alkaline first module thereby forming a solublealkali metal aluminate,

[0030] (C) a third module comprising said components of said firstmodule in combination (g) with at least one of an alkali metalphosphate, borate and sodium silicate,

[0031] (D) a fourth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source, or

[0032] (E) a fifth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source, and (g) at least one of an alkali metal phosphate, borateand sodium silicate.

[0033] In another aspect of this invention, one or more modules of amodular drilling fluid, described above, can also be used as a spottingfluid. Typically, the drilling fluid is added as a spotting fluid in awell where the mud has not previously been treated with one or more ofthe modules of the modular drilling fluid. However, one or more modulesof the modular drilling fluid can be used in drilling mud alreadytreated with one or more modules of the modular drilling fluid, as aspotting fluid.

[0034] In a final aspect of this invention, a completion fluid,containing one or more of the modules of the modular drilling fluid isalso disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1, shows a scanning electron image of a mud filter cake.

[0036]FIGS. 2A, 2B, 2C, 2D and 2E show a scanning electron image of afilter cake treated with a 1.5% or 3.0% solution of hydrogen peroxidealone.

[0037]FIGS. 3A, 3B, 3C show a scanning electron image of a filter caketreated with a 1.5% solution of hydrogen peroxide and a 0.8%concentration of module 5 of the modular drilling fluid at amagnification of ×50, ×100 and ×2000, respectively.

[0038]FIGS. 4A, 4B, 4C show a scanning electron image of a filter caketreated with a 3.0% solution of hydrogen peroxide, a 0.8% concentrationof module 5 of the modular drilling fluid at a magnification and 5.25%solution of sodium hypochlorite of ×50, ×500 and ×2000, respectively.

DETAILED DESCRIPTION OF THE INVENTION

[0039] In the present invention, the order in which the components ofthe spotting fluid of the first three aspects of this invention areadded or injected into the well is not critical. It is preferred,however, that the oxidizer is first added to the borehole so that themud filter cake will be oxidized prior to the addition of the componentwhich reacts in the well bore to generate a gas. Likewise, when alubricant is used in the spotting fluid and spotting method of thepresent invention, it can be added before the oxidizer, before the gasgenerating component, or after both the oxidizer and the gas generatingcomponent. Preferably, the lubricant, when added, is added in betweenthe oxidizer and the component which will generate gas.

[0040] The oxidizer used in the method of dislodging the stuck pipe andin the spotting fluid of this invention is a component which willoxidize the mud filter cake. Any component which will react to oxidizethe mud cake can be used. In addition, the oxidizer tends to swell themud cake. Examples of such components include hydrogen peroxide;hypochlorites, such as sodium hypochlorite, potassium hypochlorite,lithium hypochlorite, calcium hypochlorite or magnesium hypochlorite; orperoxides, such as hydrogen peroxide, alkali metal peroxides, alkalineearth metal peroxides or manganese group peroxides. Of these oxidizers,hydrogen peroxide is preferred.

[0041] The oxidizer portion of the spotting fluid and method of thepresent invention can be added or injected to the borehole alone oradded or injected as a solution. In considering handling aspects, it ispreferable that the oxidizer is added as a solution. Any acceptablecarrier can be used to form a solution with the oxidizer, so long as thecarrier does not interfere with the oxidation of the filter cake.Example of acceptable carriers include, but are not limited to, mineraloil, water, brine, etc. Typically, the carrier for the oxidizer isselected so that it is compatible with the drilling mud used in theparticular drilling operation. For example, if a water-based drillingmud is being used in the drilling operation, the oxidizer can be addedor injected into the borehole in a solution with fresh water or brine.Likewise, if an oil-based drilling mud is being used, the carrier forthe oxidizer is selected accordingly.

[0042] The concentration of the oxidizer in the solution can be up toabout 95% by weight or volume. From a practical stand point, theoxidizer is present in the solution in an amount up to 50% by weight orvolume, preferably in an amount between 1 and 10% by weight or volume,and most preferably between 1.5 and 5% by weight or volume. Preferably,the oxidizer used in the method of this invention and spotting fluidsystem is hydrogen peroxide. Preferably, the hydrogen peroxide is infresh water or brine at a concentration of about 1.5 to 5% by weight orvolume.

[0043] The oxidizer or oxidizer in solution can further contain aweighting agent. Weighting agents are added to adjust the density of theoxidizer to correspond to the density of the drilling mud used in thedrilling operation. The change in density can be an increase (positiveweighting) or a decrease (negative weighting). Examples of weightingagents include barite, hematite, calcium carbonate, iron carbonate,foams, mist and others known to those skilled in the art. Foams and mistare examples of negative weighting agents. The weighting agent is addedto the oxidizer or reducer in an amount up to about 90% by weight orvolume, however, the amount of the weighting agent will vary from wellto well. The appropriate amount of weighting agent is typicallydetermined by personnel at the drilling site.

[0044] The oxidizer is pumped through the drill pipe to the site of thestuck pipe. Once in the region of the stuck pipe, the oxidizer willoxidize, diffuse into and swell the mud filter cake. This filter cake istypically thick and “sticky” and is formed across the permeableformation in the stuck pipe section of the borehole. Often, due to theexistence of a high differential pressure between the well bore (P_(w)),and the formation pressure (P_(f)), (P_(w)>P_(f)), the filter cake growsto a point that the hole diameter becomes smaller than the externaldiameter of the drill string and the bottom hole assembly. This causesthe bottom hole assembly to stick differentially to the hole wall or tobecome imbedded in the thick filter cake.

[0045] As stated above, the addition of the oxidizer oxidizes and swellsthe filter cake and sometimes disintegrates the filter cake so that thelubricant and component which generates gas in the borehole of thepresent invention are not needed. But this usually depends on theseverity of the problem, including thickness and make-up of the mudfilter cake.

[0046] A second component of the spotting fluid or spotting process ofthe present invention is component which will react in the borehole togenerate gas. The gas can be any gas, including but not limited to,carbon dioxide, hydrogen, oxygen, nitrogen and others. The generation ofgas lowers the density of the mud filter cake surrounding the stuckportion of the pipe and creates an upward buoyancy for these mud cakeparticles. The gas pressure generated in the borehole creates ablistered and bubbling permeable formation which enables the pipe tobreak free from the mud filter cake and, hence, become unstuck. Notwishing to be bound by theory, it is believed that the gas bubblesmigrate upward through the mud column, along with the lubricant, whenpresent, thereby decreasing the well bore pressure P_(w), with respectto the formation pressure, P_(f). When P_(w)≦P_(f), the pipe will becomefree upon exertion of some mechanical pulling or turning action. Inaddition, as the generated gas is subjected to a reduced pressure, forexamples as the gas reaches the surface or permeates the filter cake,the gas expands. As the gas volume expands, the well bore pressure mustdecrease. This also causes stuck pipe differential pressure to reverseitself from P_(w>)P_(f) to P_(w)≦P_(f) thus releasing the stuck pipe anddestroying the wall filter cake.

[0047] Any component which will generate gas by reaction with anothercomponent in the borehole can be used. It is noted, however, thatcomponents which will or could have an adverse effect of the drillingoperations or which will produce hazardous byproducts should be avoided.For example, components which will react violently, or explode, shouldbe avoided. Examples of gas generating component include componentswhich will react with the oxidizer. If the oxidizer is hydrogenperoxide, examples of gas generating components include sodiumhypochlorite, potassium hypochlorite, lithium hypochlorite, calciumhypochlorite and magnesium hypochlorite; and peroxides such as alkalimetal peroxides, alkaline earth metal peroxides and manganese groupperoxides. The by-products of these components are typically salts ofthe metals, water and gas. If the oxidizer is one of the componentsmentioned above for the gas generating component, the gas generatingcomponent can be, for example, hydrogen peroxide.

[0048] Other components which will react in the borehole to generate gascan be used. These components can react with components in the drillingmud, lubricants or other additives present in the borehole. An exampleof such a component is sodium bicarbonate, which will generate carbondioxide. Sodium bicarbonate is an attractive gas generating componentsince it is relatively easy to handle, relatively inexpensive and willreact with acids or bases present in the borehole. Further, the sodiumbicarbonate may be lightened by the lubricant, polymers or waxes. In oneaspect of the present invention, an acid, such as citric acid, aceticacid, oxalic acid or other carboxylic acids, boric acid, phosphoric acidor vinegar having an acidity of 5% or more, is added to or injected intothe borehole. The acid can be added, for example, in a lubricant(discussed hereinbelow) which is injected or added to the borehole. Oncethis acid is in the borehole, the gas generating component is added andwill react with the acid to generate a gas, in this case, carbondioxide. Alternatively, the gas generating component can be added to theborehole, followed by the addition of another component which will reactwith this gas generating component.

[0049] Other examples of gas generating components include hydrazine,and manganese oxide among others. In addition, the gas generatingcomponent may react with the reducer.

[0050] The gas generating component of the spotting fluid and spottingmethod of the present invention can be added or injected to the borehole alone or added or injected as a solution. In considering handlingaspects, it is preferable that the gas generating component is added ina solution. Any acceptable carrier can be used to form a solution withthe gas generating component, so long as the carrier does not interferewith the gas generating capacity or ability of this component. Examplesof acceptable carriers include, non-toxic mineral oil, water, brine,etc. Typically, the carrier for the oxidizer is selected so that it iscompatible with the drilling mud used in the particular drillingoperation. For example, if a water-based drilling mud is being used inthe drilling operation, the gas generating component can be added orinjected into the borehole in a solution with fresh water or brine.Likewise, if an oil-based drilling mud is being used, the carrier forthe oxidizer is selected accordingly.

[0051] The concentration of the gas generating components in thesolution can be up to about 95% by weight or volume. From a practicalstand point, the gas generating component is present in the solution inan amount up to 60% by weight or volume and preferably in an amountbetween 1 and 10% by weight or volume. Preferably, the gas generatingcomponent used in the spotting method and in the spotting fluid systemof the present invention is sodium hypochlorite when the oxidizer ishydrogen peroxide. Preferably, the sodium hypochlorite is in fresh wateror brine at a concentration of about 1.0 to 10% by weight or volume.

[0052] The gas generating component or solution thereof can furthercontain a weighting agent. As stated above, weighting agents are addedto adjust the density of the gas generating component to correspond tothe density of the drilling mud used in the drilling operation. Thechange in density can be an increase (positive weighting) or a decrease(negative weighting). Examples of weighting agents include barite,hematite, calcium carbonate, iron carbonate, foams, mist and othersknown to those skilled in the art. Foams and mist are examples ofnegative weighting agents. The weighting agent is added to the gasgenerating component in an amount up to about 60% by weight or volume,however, the amount of the weighting agent will vary from well to well.The appropriate amount of weighting agent is typically determined bypersonnel at the drilling site.

[0053] Optionally, any component which acts as a reducer can also beadded to the well and can be part of the spotting fluid system. Like theoxidizer and gas generating component, the reducer can be added in asolution.

[0054] In the spotting method and spotting fluid system of the presentinvention, a lubricant can also be used or is part of the system. Anylubricant typically used in drilling operations can be used as alubricant of the present invention. Examples of lubricants include, butare not limited to, mineral oil, glycols, esters, vegetable oils,synthetic oils and fatty acid sources. In addition, drilling fluidcompositions having lubricating properties can also be used. Examples ofsuch drilling fluids include the modular drilling fluid described U.S.Pat. No. 5,755,295. This modular drilling fluid system can beconveniently formulated as at least one of the following modules:

[0055] (1) an alkaline first module that contains a source of caustic, anatural wax, and a natural thinner;

[0056] (2) a second module prepared by reacting aluminum metal with thecomponents of the alkaline first module thereby forming a soluble alkalimetal aluminate;

[0057] (3) a third module containing the components of the first modulein combination with at least one of an alkali metal phosphate, alkalimetal borate and sodium silicate;

[0058] (4) a fourth module containing the components of the first modulein combination with a C₁₋₂₄ saturated or C₂₋₂₄ unsaturated carboxylicacid source, a surfactant, and a preservative; and

[0059] (5) a fifth module containing the components of the first modulein combination with a carboxylic acid source, a surfactant, apreservative, and at least one of an alkali metal phosphate, alkalimetal borate and sodium silicate.

[0060] It has further been discovered that a combination of glycerol andphosphoric and/or boric acid added to any one of the forgoing modulescan further improve some properties of this modular drilling fluid. Theimproved properties include improved lubricity of the drilling mud, mudthinning and mud viscosity control, decreased bit “balling” tendencies,decrease in the cohesive or shearing resistance beneath the drill bitand improved control of phase separation of the mud. This modifiedmodular drilling fluid, mud and associated methods of using the modifiedfluid and mud are the subject U.S. patent application 09/083,051, filedon May 22,1998. In addition, a salt water-based drilling mud isdisclosed in U.S. patent application 09/236,568, which contains themodular drilling fluid.

[0061] Module 1

[0062] Module 1 is the principal drilling fluid additive. It can be usedalone or in combination with one or more of the other modules asdiscussed herein below. Module 1 is a caustic (alkaline) drilling fluid.Caustic can be sodium or potassium hydroxide. This composition furthercomprises one or more natural waxes and one or more natural thinner.Typically the pH of a Module 1 formulation is 11 or greater. Such a highpH increases the dispersability of the mud, thereby facilitating thedrilling operation.

[0063] A natural wax used in this composition facilitates the formationof emulsions and assists in coating solid particles released bydrilling. Exemplary natural waxes which can be used in the compositionare montan wax, waxes extracted from carnauba palm tree, cotton lintres,lignite deposits, and the like.

[0064] A natural thinner is also provided in Module 1, and as usedherein refers to a natural colloidal clay dispersion. Exemplary naturalthinners include lignins, tannins and negatively charged derivatives ofhumic acid.

[0065] The combination of caustic, natural wax, and natural thinner asdescribed above is sometimes referred to herein as a “scour kierliquor”, or its equivalent lignin and tannins and is a principalingredient of the instant drilling mud system. Preferably, the firstmodule is composed of a “scour kier liquor” which contains a caustic ata pH of 11 or above, as well as a natural wax and a natural thinner,such as a lignin and/or a tannin. The scour kier liquor referred toherein is typically obtained by the alkaline digestion of cellulosicfibers, e.g., cotton pulp, and is described further herein below.

[0066] A preferred scour kier liquor is commercially available fromBarnhardt Industries (Charlotte, N.C.). The kier liquor may also becombined with oxidizing agents such as peroxide, sodium hypochlorite,and the like.

[0067] This module may further comprise glycerol, phosphoric acid and/orboric acid, and optionally a gel. The glycerol, phosphoric acid and/orboric acid is added to produce glyceroborates e.g., glyceroboriborate,and glycerophosphates.

[0068] The addition of glycerol, in accordance with the presentinvention, boosts the lubricity of the module. This is due to glycerol'slow molecular weight and high solubility in water-based or oil basedmuds. Glycerol further facilitates the rapid diffusion of the modulardrilling fluid in the mud filter cake, porous media (e.g., rock) andclay masses adhering to the stuck section of the drill pipe. Glycerol isadded in an amount between 0.0027% by volume to 95% by volume of themodule, preferably in an amount up to 40% by volume.

[0069] Phosphoric acid and/or boric acid is added to this module.Typically, the phosphoric acid and/or boric acid is added in an amountbetween 0.0008% and 95% by volume, preferably up to 35% by volume,assuming a 70% or higher concentration of the acid. The phosphoric acidand/or boric acid will react with the glycerol in a condensationreaction to produce a phosphate, a borate ester or combination ofborophosphate esters. Due to the temperature and pressure in theborehole, a reaction of the glycerol with phosphoric acid and/or boricacid further takes place in the borehole. This reaction product has ananionic head, comprising the phosphate or the borate anions which willcoat, attach, adhere or associate with the cations on the edge of theclay particles. The attraction between the anionic heads and the cationsof the clay edges causes an increase in the total negative charges ofthe clay particles thus deflocculating or dispersing of the clay slurryor mud filter cake, clay adhering to the stuck section of the drill pipe(so-called bit “balling” phenomenon) and the weakening of the clay“cements” holding the rock grains together.

[0070] The weakening of the clay “cements” further decreases thestrength of the mud and the compressed and thickened mud wall around thestuck section of the drill string, through a capillary action by themodular drilling mud or fluid system. Once penetrating the structure ofthe clay “cement” through capillary pressure, the anionic heads of thephosphate, borate or combination borophosphate esters will deflocculateand weaken the cement. This is like driving a wedge between adjacentcemented particles in the region of the stuck pipe section.

[0071] In addition, the phosphate, borate or combination borophosphateesters will have tails that allow for solubility of the esters in thewater phase of the drilling fluid. With this solubility, the filtrate ofthe modular drilling fluid is allowed to diffuse through capillaryaction into the porous media (e.g., rock or thick, compressed mud wallin the stuck section of the pipe).

[0072] The gel is optionally added to the modular drilling mud or fluidsystem to reduce phase separation and settling of the particles duringstorage. The gel further controls the excessive loss of the componentsof the spotting fluid system to which the modular drilling fluid systemis added. Typically, the gel is added in an amount of 0.001 lb. to 100.0lb. per barrel, preferably in an amount of 0.001 to 10.0 lb. per barrel.

[0073] Module 2

[0074] This module represents a thickener or oil solidifier in whichaluminate ions have been provided. Whenever the aluminate ions are addedto the drilling fluid prior to pulling the drill assembly out of thehole, the gel strength of the mud increases. This means that thethixotropic properties of the drilling fluid can be changed as desired,thus permitting cuttings entrained in the mud to be suspended. Thismodule is added to the spotting system and method when there is a lossof thixotropic characteristics in the drilling mud. In addition,whenever any of Module 1, discussed above, and Modules 3 and 4,discussed below, are combined with oil, the addition of Module 2 causesthe oil to solidify, i.e., to a rubbery or thick grease. The degree ofoil solidification can be readily altered by adjusting the concentrationof aluminum metal, which results in a change in the concentration ofaluminate ions.

[0075] Preferably, the second module is an aluminated scour kier liquorin which aluminum metal has been reacted with the scour kier liquor toproduce aluminate ions in the presence of lignins and/or tannins. Thealuminate ions react with the lignins and tannins, thereby crosslinkingthem and increasing the cutting suspension capability of the drillingmud. Any alkali metal aluminate can be used, however, a particularlypreferred alkali metal aluminate is sodium or potassium aluminate.

[0076] A preferred Module 2 formulation can be prepared by combiningaluminum metal, in the form of shavings, fines, and the like, withsodium hydroxide or potassium hydroxide and water in the presence oflignins or tannins. In the manufacture process of the caustic soda, thecaustic reacts with the aluminum metal to produce sodium aluminate orpotassium aluminate and hydrogen gas. Some of the aluminate ions soformed react with the lignins or tannins, thereby crosslinking them. Itis believed that whenever the cross-linked product is added to a claysuspension a partially reversible net charge is placed on the clayparticles, which increases the gel strength of the mud. This is clearlyshown in Tables 1 and 2 of U.S. Pat. No. 5,755,295. This is a stronglydesired property especially while the drilling fluid is quiescent in ahorizontal, lateral, directional or deviated hole, e.g., in rivercrossing, environmental remediation wells, or trenching operations.

[0077] A suitable Module 2, or thickener, can be typically prepared byadding 0.2-1.5 lb. of Al metal to 1 bbl of scour kier liquor.

[0078] Module 3

[0079] Module 3 of the modular drilling fluid system represents aprimary thinner formulation. Functionally, this module counter-balancesModule 2. In this primary thinner composition, one least one of aninorganic phosphate, an inorganic borate and an inorganic silicate iscombined with a caustic thinning composition as in Module 1. Optionally,lignite can be combined with the other components of this module. Theresulting formulation is a high pH super thinner. Considering thecomponents of the composition, good performance at both low and hightemperatures is expected.

[0080] A particularly preferred composition with a primary thinner ofModule 3 comprises scour kier liquor (containing waxes and other organicmaterials) in combination with trisodium phosphate (TSP) and sodiumsilicate. Another preferred formulation includes scour kier liquor,lignite, and TSP, or a mono-, di-, or tri-sodium, potassium, or cesiumphosphate, sodium acid pyrophosphate, sodium orthophosphate, borates andsodium silicate. When using this composition, the waxes and otherorganic material (or lignite when it is used) can effectively coatcolloid particles to protect them from attack by contaminants whiledispersing them at the same time controllably, which produces a stablesuspension condition.

[0081] A preferred formulation for module 3 can be prepared by combiningwith 1 bbl of scour kier liquor, each of 1-50 lb of trisodium phosphate,0.25-2 lb sodium silicate, and 1-10 lb of borax. The borax is anoptional component that is useful in some applications.

[0082] Whenever lignite and hot water are used in an amount of about 1.0to 3.0 pounds per gallon of hot water and, for example, TSP is added,the viscosity of this newly discovered reaction product can be variedfrom about that of water, representing a thin fluid, to that of a solidtar or asphalt, a very thick material. This material can be used, forinstance, to plug a fracture in the hole or to prevent mud losses fromthe hole. This variation in viscosity is due to variations in theconcentration of TSP in the composition.

[0083] Module 4

[0084] This module provides a secondary thinner formulation as well as asurfactant and preservative, which can be combined with any of theprevious modules as needed.

[0085] Preferred components in this module are those which enhance theemulsification of oil, such as a saturated or unsaturated carboxylicacid rich source, e.g., vegetable oil or a natural ester such ascottonseed oil, jojoba oil, and the like. Preferably, the carboxylicacid source is a C₁₋₂₄ saturated or C₂₋₂₄ unsaturated carboxylic acid ora synthetic ester, such as, polyalphaolefin. This component affords asecondary thinning capability. Other preferred anionic or nonionicemulsifiers (surfactants) include those having a suitable HLB(hydrophilic-lipophilic balance), alkylbenzene sulfonates, tergitol, orTRITON (available from Union Carbide Corp., Danbury, Conn.).

[0086] The preservative present in this module helps to protect againstbacteria and is preferably a chelating agent, such as table salt,driller salt and salts of ethylenediamine tetraacetate (EDTA) and borax.Other suitable preservatives include boric acid or derivatives thereofand salt.

[0087] A representative formulation of this module is as follows in awater base (1 bbl): 1-10 lb borax, 0.5-10 lb borateam (which includes asulfonated alkyl benzene-anionic surfactant), and 0.2-1 lb EDTA (Na or Ksalt). About 0.5-10 lb of TRITON (a nonionic surfactant) can also beoptionally provided.

[0088] The carboxylic acid of module 4 will also react with the organicor inorganic acid of phosphoric acid and/or boric acid, when present.This reaction occurs in the bore hole under the temperature and pressureof bore hole. The reaction product is a phosphate lipid, a borate lipidor a combination borophosphate lipid. Like the phosphate esters andborate esters described above, the phosphate lipid and borate lipidshave anionic head which are attracted to the cations of the edge of theclay particles. Hence, these lipids have a similar function and effectas the esters described above.

[0089] Module 5

[0090] This module represents a combination of Modules 1, 3 and 4discussed above. This composition is asuper-thinner-dispersant-lubricant formulation that is preferably usedin treatments of 0.5 to 2.0% by volume in the mud system, such as freshwater mud, lime mud or salt mud. Use of this combination of Modules 1,3, and 4 increases the deflocculation, lubricity and thinningdramatically.

[0091] Functionally, in the combined modules a polymerized phosphateand/or borate ester is formed which possesses the high lubricityproperties of esters as well as the thinning capabilities of negativelycharged phosphate and/or borate ions. The amount of esterification canbe easily altered by adjusting the concentration of phosphate and/orborate.

[0092] A preferred composition for this module, is formed by combiningthe compositions of modules 1, 3, and 4 in the amounts detailed abovewith an oil base. Preferably, the oil, such as cottonseed oil or asynthetic oil like polyalpholefin (PAO), is provided in an amount up to90% of the total volume. Preferably up to 10%, but optionally up to 20%,of the oil content can be replaced with a mineral oil, such as FGA.

[0093] The composition identified herein as formulation (I) is composedof scour kier liquor (SKL) or equivalent lignin and tannins, TSP, sodiumacid pyrophosphate (SAPP), borax, borateam, cottonseed oil and water inthe relative amounts indicated above.

[0094] Each of the forgoing modules can further contain additives suchas graphite, to improve the color of the composition. In addition otheradditives can be added to improve the smell of the modules. Theseadditives will be readily apparent to those skilled in the art andshould be selected so that the properties of the drilling mud are notadversely affected.

[0095] In the spotting method and spotting fluid system of the presentinvention, the preferred lubricant is module 5 of the modular drillingfluid. Particularly preferred is module 5 containing glycerol, andphosphoric and/or boric acid. This provides the best all-aroundproperties for the spotting fluid and spotting method of the presentapplication.

[0096] In the preferred spotting method of the present invention theoxidizer, lubricant and gas generating component are added or injectedinto the borehole in the following manner.

[0097] First, a “head” portion or “pill” is added or injected into theborehole. The head portion contains the oxidizer which will oxidize themud cake in the stuck region.

[0098] Second, a “middle” portion or “pill” is then added or injectedinto the borehole. This middle portion contains a lubricant describedabove which lubricates the oxidized parts of the mud cake.

[0099] Third, a “tail” portion or “pill” is then added or injected intothe borehole. This tail portion is reactive in the borehole and resultsin the generation of bubbles of gas, thereby reducing the density of themud surrounding the stuck portion and generating upward buoyancy. Thegas pressure creates a blistered and bubbling mud cake or mud whichenables the pipe to move, hence become unstuck. The formation of gasbubbles creates a system wherein the pressure in the stuck region isless than or equal to the mud column pressure. In other words, thereaction causes the differential pressure to be equalized or reversed(P_(w)≦P_(f)), thus releasing the differentially stuck pipe. Moreover,the buoyancy, lubricity plus oxidation and/or reduction ordisintegration of the thick and compressed cake results in the cakehaving no cohesion, whereby it is lifted upwardly, facilitatingelimination of the stuck portion. The reaction is usually with theoxidizer in the head portion and components present in the lubricant.

[0100] The head portion preferably contains hydrogen peroxide or sodiumbicarbonate w in a solution. The concentration of the hydrogen peroxideor sodium bicarbonate in the solution is preferably about 1.5 to 10.0%by weight or volume of the solution, preferably 1.5 to 5.0% by weight orvolume.

[0101] The lubricant is then added or injected into the borehole. As isstated above, the preferred lubricant is module 5 of the modulardrilling fluid of application Ser. No. 09/083,051, filed on May 22,1998. This module, with its high concentration of an oil, e.g. vegetableoil may also provide for lifting of the mud cake, in addition to thelubricating action. This module can be charged with sodium bicarbonate.

[0102] Finally, after addition of the lubricant, the component whichwill generate gas bubbles is added to the well. Preferably, thecomponent is sodium hypochlorite and/or acids, such as citric acid,acetic acid, other carboxylic acids, boric acid, phosphoric acid,vinegar having an acidity of 5% or more, dilute hydrochloric acid, or amud acid. The preferred form to add sodium hypochlorite is as a solutionin water or brine at a concentration of about 1 to 50% by weight orvolume, preferably 1-10% by weight or volume.

[0103] Examples of possible gas generation reactions which can be usedin the present invention include, but are not limited to, any one of thefollowing equations:

[0104] 1. Sodium bicarbonate and citric acid

3NaHCO₃→3Na⁺+3(HCO₃)⁻

3Na⁺+3(HCO₃)⁻+C₆H₈O₇(citric acid)→3CO₂↑+Na₃C₆H₅O₇.3H₂O

[0105] 2. Sodium bicarbonate and boric acid

NaHCO₃→Na⁺+(HCO₃)⁻

(HCO₃)⁻+B(OH)₃→CO₂↑+B(OH)₄ ⁻

[0106] 3. Calcium phosphate and sodium bicarbonate

Ca(H₂PO₄)₂.2H20+2NaHCO₃→2CO₂↑+4H₂0+Na₂Ca(HPO₄)₂

[0107] 4. Hydrazine reactions to give nitrogen

N₂H₄+4OH⁻→N₂↑+4H₂O

N₂H₄+O₂→N₂↑+2H₂O

[0108] 5. Hydrogen peroxide and sodium hypochlorite

H₂O₂+NaOCl→H₂O+NaCl+₂↑

[0109] 6. Permanganate and oxalic acid

2MnO₄(aq)+6H⁺+5H₂C₂O₄→2Mn²⁺+10CO₂↑+8H₂O

[0110] 7. Acetic acid and Sodium bicarbonate

2NaHCO₃→2Na⁺+2(HCO₃)⁻

2Na⁺+2(HCO₃)⁻+HC₂H₃O₂(acetic acid)→CO₂↑+Na₂CO₃+H₂O +H⁺+[C₂H₃O₂]⁻

[0111] Finally, it has been discovered that the addition of hydrogenperoxide in a solution water or brine, can dislodge a stuck pipe, alone,if the drilling mud is a drilling mud comprising, as a drilling fluid,at least one of the following modules (A)-(E)

[0112] (A) an alkaline first module that contains (a) a source ofcaustic, (b) a natural wax, (c) a natural thinner, (d) glycerol, and (e)phosphoric acid and/or boric acid,

[0113] (B) a second module prepared by reacting (f) aluminum metal withthe components of said alkaline first module thereby forming a solublealkali metal aluminate,

[0114] (C) a third module comprising said components of said firstmodule in combination (g) with at least one of an alkali metalphosphate, borate and sodium silicate,

[0115] (D) a fourth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source or a synthetic ester such as polyalphaolefin, or

[0116] (E) a fifth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source, and (g) at least one of an alkali metal phosphate, borateand sodium silicate.

[0117] Surprisingly, it has also been discovered that at relatively lowconcentrations of hydrogen peroxide to a borehole having a stuck pipe,will result in the freeing of the stuck pipe. Prior art method usinghydrogen peroxide required high concentrations of hydrogen peroxide. Inthe present invention, the concentration of hydrogen peroxide can be alittle as 1.5% and is preferable in a concentration of less than 5.0%.

[0118] It has also been discovered that the addition of one of themodules of the modular drilling fluid can be effective as a stuck pipetreatment. As is shown in Example 1 below, the addition of module 5 ofthe modular drilling fluid will effectively release a stuck pipe.

[0119] The amount of each of the pills of the spotting fluid in thepresent invention used to release a stuck pipe varies depending on thediameter of the hole, the length of the stuck section, and the otherfactors, such as fluid loss in the formation. Typically, an excessamount of the pills is added to the well to account for losses and toextend above and below the stuck section of the pipe. In the presentinvention, the amount of the individual pills or entire spotting systemgenerally ranges between 1 and 1000 bbl.

[0120] The inventor has also discovered that a completion fluid,containing one of the forgoing modules is also effective in the methodsof this patent. A completion fluid is added to the hole to displace themud and the completion fluid contains no solids. The completion fluidinvades the formation and physically plugs and prevents flow from thewell. Typically, a completion fluid is water or brine with heavy geland/or polymeric components. The inventor has found that adding one ofthe modules of the modular drilling fluid to these components, a veryeffective completion fluid is prepared.

[0121] The invention will now be described by way of examples whichillustrate the present invention but do not limit it.

EXAMPLE 1

[0122] One hundred fifty gallons of Module 5 is prepared by mixing 75gallons cottonseed oil(with preservatives), 1 quart of glycerol, 1 quartof phosphoric acid, 4 lb. of gel, 42 gallons of water, 10 lb. of salt(NaCl), 1 quart of EDTA, 1 quart of boric acid, 10 lb. of borateem, 6lb. of borax, 12 gallons of hot water (150° F.), 30 lb. of trisodiumphosphate, 25 lb. of lignite, 1 quart of caustic soda, 25 lb. ofgraphite.

[0123] 125 gallons of Module 5 was added to a well having a stuck casingin Mississippi Canyon Field. Approximately 200 barrels of a drilling mudwas present in the spotting operation. After Module 5 was added to thearea of the stuck portion of the pipe and allowed to soak, surprisinglyafter about 20 minutes to about one hour the casing was released fromthe formation by applying mechanical force to the drill string.

EXAMPLE 2

[0124] (Preparation of the Filter Cake)

[0125] A mud filter cake was prepared containing bentonite (gel), aweighting agent comprising barite, water, Module 5, prepared in Example1 above, caustic soda, lignite and sodium polyacrylamide. The mud filtercake was formed in accordance with the API standard of 100 psi pressuredifferential and 30 min. time of filtration.

EXAMPLE 3

[0126] The mud filter cake prepared in accordance with Example 2, wastreated with a 1.5% or 3.0% solution of hydrogen peroxide and allowed tosoak for a period of time. The scanning electron images are show in thefigures of FIG. 2. FIG. 2A shows, at ×50 magnification, a filter caketreated with a 1.5% solution of hydrogen peroxide alone. FIG. 2B showsthe same treated mud at ×1000 magnification. (FIG. 2C) shows the mudfilter cake treated with a 3.0% solution of hydrogen peroxide alone, at×50 magnification, and (FIG. 2D), shows the same at ×1000 magnification.

[0127] Comparing these figures to FIG. 1, it can be seen that thehydrogen peroxide tends to form potholes in the mud filter cake whichindicates a disintegration of the sticky, thick mud filter cake.Further, it can be seen that the 3% solution of the hydrogen peroxide ismore effective at oxidizing the mud filter cake than the 1.5% solutionof hydrogen peroxide.

EXAMPLE 4

[0128] The mud filter cake prepared in accordance with Example 2, wastreated with a 1.5% solution of hydrogen peroxide and allowed to soakfor a period of time. Then an addition of 0.8% concentration of Module5, prepared in Example 1 was added to the filter cake and allowed tosoak. FIGS. 3A, 3B and 3C show a scanning electron image of a filtercake at a magnification of ×50, ×100 and ×2000, respectively. Again notethe formation of potholes in the filter cake which shows that thecombination of the hydrogen peroxide and the Module 5 are effective atdisintegrating, the mud filter cake.

EXAMPLE 5

[0129] The mud filter cake prepared in accordance with Example 2, wastreated with a 3.0% solution of hydrogen peroxide and allowed to soakfor a period of time. Then an addition of 0.8% concentration of Module5, prepared in Example 1 was added to the filter cake and allowed tosoak. Finally, a 5.25% solution of sodium hypochlorite was added to thefilter cake. FIGS. 4A, 4B, 4C show a scanning electron image of a filtercake treated at ×50, ×500 and ×2000, magnification, respectively. As canbe seen, the addition of all three components to the mud filter cake,the potholes formed in the mud filter cake are larger, indicating theoxidation, blistering and removal or lifting of particles from thefilter cake by the generation of the oxygen gas from the reaction of thehydrogen peroxide and the sodium hypochlorite. The combination of thehydrogen peroxide and sodium hypochlorite is very effective in releasingstuck pipes.

[0130] It is additionally pointed out that the sodium hypochlorite couldbe added to the filter cake before the addition of the hydrogenperoxide. Stated another way, the order in which the components of thespotting fluid and method of the present invention are added to aborehole can be reversed.

What is claimed is:
 1. A method for dislodging a stuck pipe in a wellbore of a downhole well drilling operation comprising adding to theborehole in the region of the stuck pipe: 1) an oxidizer; 2) at leastone component which reacts in the well bore to generate a gas; and 3)optionally, a reducer.
 2. The method of claim 1 , wherein the componentwhich reacts in the well bore to generate a gas reacts with the oxidizeror reducer to generate said gas.
 3. The method of claim 1 , wherein thegenerated gas is carbon dioxide, hydrogen, oxygen, nitrogen, or acombination thereof.
 4. The method of claim 2 , wherein the gasgenerating component is selected from the group consisting of hydrazine,sodium bicarbonate, manganese oxide and hydrogen peroxide.
 5. The methodof claim 1 , further comprising adding (4) a lubricant or a penetrationrate enhancer to the well bore.
 6. The method of claim 5 , wherein thelubricant is added to the well bore between the oxidizer and thecomponent which reacts in the well bore to generate a gas.
 7. The methodof claim 5 , wherein the lubricants or penetration rate enhancer isselected from the group consisting of synthetic esters or syntheticesters in combination with vegetable oil, surfactants, mineral oil,glycol, glycerol, alcohols, low toxicity hydrocarbon or mixturesthereof.
 8. The method of claim 5 , wherein the lubricant is a drillingfluid comprising at least one of the following drilling fluid modules(A)-(E): (A) an alkaline first module that contains (a) a source ofcaustic, (b) a natural wax, (c) a natural thinner, (d) glycerol, and (e)phosphoric acid and/or boric acid; (B) a second module prepared byreacting (f) aluminum metal with the components of said alkaline firstmodule thereby forming a soluble alkali metal aluminate; (C) a thirdmodule comprising said components of said first module in combination(g) with at least one of an alkali metal phosphate, borate and sodiumsilicate; (D) a fourth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source, and optionally a synthetic oil and a surfactant, and/or (E)a fifth module comprising said components of said first module incombination with (h) a saturated or unsaturated carboxylic acid source,and (g) at least one of an alkali metal phosphate, borate and sodiumsilicate.
 9. The method of claim 8 , wherein the lubricant orpenetration rate enhancer comprises the fifth module of the modulardrilling fluid.
 10. The method of claim 1 , further comprising the stepof applying mechanical force to the drill string after the addition ofthe components to the well bore.
 11. The method of claim 1 , wherein theoxidizer is hydrogen peroxide.
 12. The method of claim 2 , wherein thecomponent which reacts with the oxidizer is a hypochlorite or aperoxide.
 13. The method of claim 12 , wherein the hypochlorites areselected from the group consisting of sodium hypochlorite, potassiumhypochlorite, lithium hypochlorite, calcium hypochlorite and magnesiumhypochlorite; and the peroxide is selected from the group consisting ofhydrogen peroxide alkali metal peroxides, alkaline earth metal peroxidesand manganese group peroxides.
 14. The method of claim 12 , wherein thecomponent which reacts with the oxidizer is sodium hypochlorite.
 15. Themethod of claim 11 , wherein the hydrogen peroxide is added to the wellin a solution with fresh water or brine, the concentration of thehydrogen peroxide is between about 1.5% to about 5.0% by weight orvolume.
 16. The method of claim 14 , wherein the sodium hypochlorite isadded to the well in a solution with fresh water or brine, theconcentration of the sodium hypochlorite is between about 1.0 and 10.0%by weight or volume.
 17. The method of claim 5 , wherein the componentwhich reacts in the well bore reacts with a component in the lubricantor penetration rate enhancer.
 18. The method of claim 17 , wherein thecomponent which reacts in the well bore is sodium bicarbonate.
 19. Themethod of claim 18 , wherein the lubricant or penetration rate enhancercontains an acid which will react with the sodium bicarbonate.
 20. Aspotting fluid system for dislodging a stuck pipe in a well bore of adownhole well drilling operation comprising: 1) an oxidizer; 2) at leastone component which reacts in the well bore to generate a gas; and 3)optionally a reducer.
 21. The spotting fluid system of claim 20 ,further comprising a lubricant or a penetration rate enhancer.
 22. Themethod of claim 21 , wherein the lubricant is at least one of thefollowing drilling fluid modules (A)-(E): (A) an alkaline first modulethat contains (a) a source of caustic, (b) a natural wax, (c) a naturalthinner, (d) glycerol, and (e) phosphoric acid and/or boric acid; (B) asecond module prepared by reacting (f) aluminum metal with thecomponents of said alkaline first module thereby forming a solublealkali metal aluminate; (C) a third module comprising said components ofsaid first module in combination (g) with at least one of an alkalimetal phosphate, borate and sodium silicate; (D) a fourth modulecomprising said components of said first module in combination with (h)a saturated or unsaturated carboxylic acid source or synthetic ester,and/or (E) a fifth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source, and (g) at least one of an alkali metal phosphate, borateand sodium silicate.
 23. The spotting fluid system of claim 20 , whereinthe oxidizer is hydrogen peroxide or sodium hypochlorite.
 24. Thespotting fluid system of claim 20 , wherein the component which reactsin the borehole to generate gas is a hypochlorite or a peroxide.
 25. Thespotting fluid system of claim 24 , wherein the hypochlorites areselected from the group consisting of sodium hypochlorite, potassiumhypochlorite, lithium hypochlorite, calcium hypochlorite and magnesiumhypochlorite; and the peroxide is selected from the group consisting ofhydrogen peroxide, alkali metal peroxides, alkaline earth metalperoxides and manganese group peroxides.
 26. The spotting fluid systemof claim 25 , wherein the hypochlorite is sodium hypochlorite.
 27. Thespotting fluid system of claim 21 , wherein the oxidizer is hydrogenperoxide, the drilling fluid is the fifth module, and the componentwhich reacts in the borehole to generate gas is sodium hypochlorite. 28.An article of manufacture comprising the spotting fluid system of claim20 , wherein a first container comprises the oxidizer, a secondcontainer comprises at least one component which reacts in the well boreto generate a gas.
 29. An article of manufacture comprising the spottingfluid system of claim 22 , wherein a first container comprises theoxidizer, a second container comprises at least one component whichreacts in the well bore to generate a gas and the third containercomprises one of the modules of the modular drilling fluid.
 30. Thearticle of manufacture of claim 29 , wherein the first containercomprises hydrogen peroxide, the second container comprises sodiumhypochlorite, and the third container comprises the fifth module of thedrilling fluid.
 31. A method of dislodging a stuck pipe in a borehole ofa down hole well drilling operation using a drilling mud comprising, asa drilling fluid, at least one of the following modules (A)-(E) (A) analkaline first module that contains (a) a source of caustic, (b) anatural wax, (c) a natural thinner, (d) glycerol, and (e) phosphoricacid and/or boric acid, (B) a second module prepared by reacting (f)aluminum metal with the components of said alkaline first module therebyforming a soluble alkali metal aluminate, (C) a third module comprisingsaid components of said first module in combination (g) with at leastone of an alkali metal phosphate, borate and sodium silicate, (D) afourth module comprising said components of said first module incombination with (h) a saturated or unsaturated carboxylic acid source,or (E) a fifth module comprising said components of said first module incombination with (h) a saturated or unsaturated carboxylic acid source,and (g) at least one of an alkali metal phosphate, borate and sodiumsilicate; said method comprising adding to the borehole a solutioncomprising (I) hydrogen peroxide and (ii) water or brine.
 32. The methodof claim 31 , wherein the concentration of the hydrogen peroxide in thesolution is about 1.5% to about 5.0% by weight or volume.
 33. Acompletion fluid comprising water or brine, a gel and at least one ofthe following at least one of the following modules (A)-(E) of a modulardrilling fluid: (A) an alkaline first module that contains (a) a sourceof caustic, (b) a natural wax, (c) a natural thinner, (d) glycerol, and(e) phosphoric acid and/or boric acid, (B) a second module prepared byreacting (f) aluminum metal with the components of said alkaline firstmodule thereby forming a soluble alkali metal aluminate, (C) a thirdmodule comprising said components of said first module in combination(g) with at least one of an alkali metal phosphate, borate and sodiumsilicate, (D) a fourth module comprising said components of said firstmodule in combination with (h) a saturated or unsaturated carboxylicacid source, or (E) a fifth module comprising said components of saidfirst module in combination with (h) a saturated or unsaturatedcarboxylic acid source, and (g) at least one of an alkali metalphosphate, borate and sodium silicate.
 34. A method of dislodging astuck pipe in a borehole of a downhole well drilling operationcomprising adding to the well at least one of the following modules(A)-(E) of a modular drilling fluid: (A) an alkaline first module thatcontains (a) a source of caustic, (b) a natural wax, (c) a naturalthinner, (d) glycerol, and (e) phosphoric acid and/or boric acid, (B) asecond module prepared by reacting (f) aluminum metal with thecomponents of said alkaline first module thereby forming a solublealkali metal aluminate, (C) a third module comprising said components ofsaid first module in combination (g) with at least one of an alkalimetal phosphate, borate and sodium silicate, (D) a fourth modulecomprising said components of said first module in combination with (h)a saturated or unsaturated carboxylic acid source, or (E) a fifth modulecomprising said components of said first module in combination with (h)a saturated or unsaturated carboxylic acid source, and (g) at least oneof an alkali metal phosphate, borate and sodium silicate.